is it possible to paste contours to others glyphs with keep the orignal content

To put it simply, I want to add an outer square to all glyphs in bulk, so I can proceed with further size transformations or other tasks. Thus, I drew a box, but when I select multiple other glyphs and paste inside, the original content of the other glyphs is cleared at the same time of pasting.
What I want to ask is, how to add an outer box or another shape in bulk to all glyphs without destroying the original content.

I think you will have to paste the contours to one glyph at a time in Glyph Edit mode.

By using shortcuts to navigate to the next glyph, this process is not difficult for a few dozen glyphs. Alt+Right, Ctrl+V, Alt+Right, Ctrl+V …

If you need to edit hundreds of glyphs, you might need to look for a better solution.

http://forum.high-logic.com:9080/t/how-can-i-insert-synthetic-glyphs-into-multiple-glyphs-at-once/8215/1
from this post I had got the answer, I can reach the result which my wanted. the key point is the button “insert glyph to composite glyph”. attachments are some picture to show this.
sample2 2024-05-02 204856.png
sample1 2024-05-02 204856.png